#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Copyright 2020 Alibaba Group Holding Limited. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#


from graphscope.framework.app import AppAssets
from graphscope.framework.app import not_compatible_for
from graphscope.framework.app import project_to_simple

__all__ = ["degree_centrality"]


@project_to_simple
@not_compatible_for("arrow_property", "dynamic_property")
def degree_centrality(graph, centrality_type="both"):
    """The degree centrality values are normalized by dividing
    by the maximum possible degree in a simple graph n-1 where
    n is the number of nodes in G.

    Args:
        graph (:class:`Graph`): A simple graph.
        centrality_type (str, optional): Available options are in/out/both.
            Defaults to "both".

    Returns:
        :class:`graphscope.framework.context.VertexDataContextDAGNode`:
            A context with each vertex assigned with the computed degree centrality, evaluated in eager mode.

    Examples:

    .. code:: python

        >>> import graphscope
        >>> from graphscope.dataset import load_p2p_network
        >>> sess = graphscope.session(cluster_type="hosts", mode="eager")
        >>> g = load_p2p_network(sess)
        >>> # project to a simple graph (if needed)
        >>> pg = g.project(vertices={"host": ["id"]}, edges={"connect": ["dist"]})
        >>> c = graphscope.degree_centrality(pg, centrality_type="both")
        >>> sess.close()
    """
    centrality_type = str(centrality_type)
    return AppAssets(algo="degree_centrality", context="vertex_data")(
        graph, centrality_type
    )
